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Stock 302, to rebuild or to swap?

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    Stock 302, to rebuild or to swap?

    85 GM 302. Runs like dog shit over 3000.
    2 things. How do i get around the in cat o2 sensor? (besides a liar box)
    Anyway the car has 147k and im looking to either rebuild and build up from there or to wait till it goes out and swap.

    Opinions? Thoughts? Suggestions?

    Id love to drop a 350 chevrolet in there and stroke it to a 492 but eh...we all dream.
    1985 Mercury Grand Marquis ls-302 CFI
    Carb swap planned .
    c90 heads
    475 lift cam
    Weind stealth intake(looking for reasonable air gap or manifold for 2bblsidedraft)
    Built aod(want c6 tryin to fin vac mod model)
    331 stroker kit
    Work in progress

    #2
    I didn't think any of our cars had sensors inside the cat...just in the exhaust manifolds. 85 and older cars with CFI only have one, IIRC. I don't own one so I could be wrong.
    sigpic


    - 1990 Ford LTD Crown Victoria P72 - the street boat - 5.0 liter EFI - Ported HO intake/TB, 90 TC shroud/overflow, Aero airbox/zip tube, Cobra camshaft, 19lb injectors, dual exhaust w/ Magnaflows, Cat/Smog & AC delete, 3G alternator, MOOG chassis parts & KYB cop shocks, 215/70r/15s on 95-97 Merc rims

    - 2007 Ford Escape XLT - soccer mom lifted station wagon - 3.0 Duratec, auto, rear converter delete w/ Magnaflow dual exhaust

    - 2008 Mercury Grand Marquis Ultimate Edition - Daily driver - 4.6 2 valve Mod motor, 4R75E, 2.73s. Bone stock

    Comment


      #3
      I could be looking at it wrong or in might not be an o2 sensor....but damnit theres a thing going into the thing and its preventing me from doing STUFF! lol.
      Theres a heat shield around the cat. so i suppose it COULD be pre cat. but there IS an o2 sensor in the passenger side manifold. so i dont think there would be two pre cat sensors
      1985 Mercury Grand Marquis ls-302 CFI
      Carb swap planned .
      c90 heads
      475 lift cam
      Weind stealth intake(looking for reasonable air gap or manifold for 2bblsidedraft)
      Built aod(want c6 tryin to fin vac mod model)
      331 stroker kit
      Work in progress

      Comment


        #4
        There would be an air injection pipe running to your exhaust at or near the cats..I don't have any experience with anything but SEFI cars so I dunno what your set up is like.

        http://www.p71interceptor.com/underc...9stationwagon/

        that's an 89 country squire wagon, you can see the air injection pipes running to the front converters - sefi cars have 4 total
        sigpic


        - 1990 Ford LTD Crown Victoria P72 - the street boat - 5.0 liter EFI - Ported HO intake/TB, 90 TC shroud/overflow, Aero airbox/zip tube, Cobra camshaft, 19lb injectors, dual exhaust w/ Magnaflows, Cat/Smog & AC delete, 3G alternator, MOOG chassis parts & KYB cop shocks, 215/70r/15s on 95-97 Merc rims

        - 2007 Ford Escape XLT - soccer mom lifted station wagon - 3.0 Duratec, auto, rear converter delete w/ Magnaflow dual exhaust

        - 2008 Mercury Grand Marquis Ultimate Edition - Daily driver - 4.6 2 valve Mod motor, 4R75E, 2.73s. Bone stock

        Comment


          #5
          You don't have any in-cat O2 sensors. Later model SEFI cars had two O2 sensors, one in each manifold. I believe that your car only has one, though, in one of the exh manifolds. Nothing in the cat. Are you talking about the air injection pipes?

          There are a number of things you may need to do to the CFI system in order to not make it run like poo, but it will still be a granny motor. There are a number of CFI experts on this forum, but I'm not one of them.
          Originally posted by gadget73
          There is nothing more permanent than a temporary fix.
          91 Mercury CP, Lopo 302, AOD, 3.08LSD. 3g upgrade, Moog wagon coils up front, cc819s in the back. KYB GR-2 police shocks. Energy suspension control arm bushings. Smog deleted.
          93 F-150 XLT, 302, ZF 5-spd from 1-ton, 4wd.
          Daily--07 Civic Coupe. Bone stock with 25k miles
          Wife--14 Subaru Outback. 6-speed.
          95 Subaru Legacy Wagon--red--STOLEN 1/6/13

          Comment


            #6
            "Air Injection" would that be EGR? And still...how do i bypass?
            1985 Mercury Grand Marquis ls-302 CFI
            Carb swap planned .
            c90 heads
            475 lift cam
            Weind stealth intake(looking for reasonable air gap or manifold for 2bblsidedraft)
            Built aod(want c6 tryin to fin vac mod model)
            331 stroker kit
            Work in progress

            Comment


              #7
              Ah makes sense. Ive never seen an ox sensor with a metal line off of it.
              1985 Mercury Grand Marquis ls-302 CFI
              Carb swap planned .
              c90 heads
              475 lift cam
              Weind stealth intake(looking for reasonable air gap or manifold for 2bblsidedraft)
              Built aod(want c6 tryin to fin vac mod model)
              331 stroker kit
              Work in progress

              Comment


                #8
                EGR is different. air injection is to help burn up unburnt fuel without sending it back through the engine like the EGR does. the air injection system pumps air into the cats to help warm them up and then pumps into the heads or exhaust manifolds (depending on how old it is) to help give the cats more o2 to help burn off the unburnt fuel that gets to them. removing it depends on the version you have and emissions status in your area. pretty much removing the smog pump and the small pipes that go into the side of the cats and plugging up the lines to the heads/exhaust manifolds will bypass it. Plug any vacuum lines going to the smog pump and diverter valve and you're pretty much done after putting on a shorter belt if you still have A/C. I still have a year of emission testing before I can get away with removing that crap from my 88.

                Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
                rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)
                Originally posted by gadget73
                ... and it should all work like magic and unicorns and stuff.
                Originally posted by dmccaig
                Overhead, some poor bastards are flying in airplanes.

                Comment


                  #9
                  sweet action. I fucking hate newer cars. im this close to putting a 32v 460 in it and saying fuck it to the rest.
                  As for the bypass. ive got limited tool availabilty unless im at the shop but i cant get the vehicle to my shop as its not tagged and OKC cops are flippin Nazis
                  1985 Mercury Grand Marquis ls-302 CFI
                  Carb swap planned .
                  c90 heads
                  475 lift cam
                  Weind stealth intake(looking for reasonable air gap or manifold for 2bblsidedraft)
                  Built aod(want c6 tryin to fin vac mod model)
                  331 stroker kit
                  Work in progress

                  Comment


                    #10
                    the simplest bypass is to take the vacuum line off the smog pump (under the A/C compressor) and plug the line. do the same with the diverter valve and it's bypassed. The rest is just removal of dead weight.

                    Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
                    rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)
                    Originally posted by gadget73
                    ... and it should all work like magic and unicorns and stuff.
                    Originally posted by dmccaig
                    Overhead, some poor bastards are flying in airplanes.

                    Comment

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